With the amount of sandy soil conditions, it appears to me that Pre-M products will not stay in the soil anyway. If there is no clay or organic mater to bond to.....the product just washes down and out.l
What is your proven methods for sandy loam soils.?
I have quite a few that is sandy loam and have to switch from Pendimethalin to Prodiamine and then finally to Simazine after frost.
This kicks my butt as it is time consuming but gets the job done. We don't have the long season of growing you do in the tropic zone...............I guess this is a big factor for you guys.